Added recipes for Glslang and GLM.

recipes/glm/recipe.py

@@ -0,0 +1,11 @@
+
+import os
+from SCons.Script import *
+
+def cook(env: Environment, git_ref: str = "master") -> dict:
+    repo = env.Cook('GitBranch', repo_name = 'glm', remote_url = 'https://github.com/g-truc/glm.git', git_ref = git_ref)
+    checkout_root = repo['checkout_root']
+
+    return {
+        'CPPPATH': [checkout_root],
+    }